Hi,
that’s the same method Thorsten described in
https://forum.kurviger.com/t/beta-export-garmin-compatible-gpx/459/3
This method works also on BMW Nav 5/6 and - as far as I know - on newer Garmin Zumos 590/595.
But - of course - with all disadvantages discussed in that and in other threads.
Regards
Markus